Today we honor St. Luke, and there is no one more deserving of honor. A good start for viewing Luke is to read the opening sentence of his Gospel.
Since many have undertaken to complete a narrative of the events that have been fulfilled among us, just as those who were eyewitnesses from the beginning, and ministers of the word have handed them down to us. I too have decided, after investigating everything accurately anew, to write down an orderly sequence for you.
There, Luke make no claim to be inspired by God. He said, rather, that he had gathered stories from several sources. Scholars who have studied Luke’s text over a lifetime give us a rough three-way division for the source of his stories.
Luke takes a third of his stories from Mark’s Gospel that had been circulating for years before Luke wrote. (Matthew borrowed the same bits from Mark.) Then, about another third of Luke’s narrative is also found in Matthew, but not in Mark or John. ( As an example of that, most of the items that go to make up the Sermon on the Mount in Matthew’s Gospel are found in Luke, beginning with Luke saying that Jesus, instead of going up on a mountain, came on a level stretch.)
The other third of Luke’s Gospel are those most precious parts, like the Annunciation and the birth of Jesus. His exclusive stories of God’s mercy, such as that of the Prodigal Son are worth more than all the money in the world.
Paul referred to Luke as “our beloved physician,” but we know nothing more about Luke’s skills there.
Luke is as well the author of the Acts of the Apostles. He sneaks himself into that narrative in Chapter Sixteen. From the beginning of that chapter the narrative featured the journeying of Paul, Silas, and Timothy, with verse 5 saying, “They travelled through the Phrygian and Galatian territory.”
Then, with no explanation of who he was or of how he got there, Luke became part of the narrative in verse 11. Which reads, “We set sail from Troas.” From everything he says, Luke gives us the understanding that he is the only Gentile to compose a book of the Bible.